1. Technical Field
The present invention relates generally to data recovery in computer systems. More specifically, the present invention provides an improved method and system with redundancy for recovering lost data in individual hard drives.
2. Description of Related Art
Hard disk drives (“hard drives”) are the main data storage devices for most computers or processors. Typical hard drives contain a number of hard disk platters (“disks”) coated with magnetic material for storing data in magnetized form. The disks are affixed to a spindle that spins them in unison at a constant rate. An actuator arm moves one or more read/write heads radially across the disks to retrieve or store the magnetized data. The hard drive's components (disks, spindle, actuator arm, read/write heads, associated motors and electronics, etc.) are enclosed within a head disk assembly (HDA).
The HDA protects the hard drive's components from contamination by dust, condensation, and other sources. Contamination of a hard drive's disk or read/write head can result in disk failure, head crash and/or an unrecoverable loss of data. Also, data loss can be caused by other hard drive problems, such as electronic malfunctions, physical shocks, worn out components, improperly manufactured disks, etc.
Notably, unrecoverable data error rates for the existing generation of hard drives have remained essentially unchanged for the past 10 years. However, the storage capacity of hard drives has increased at a substantial rate (e.g., doubling on average every 18 months). In fact, the typical storage capacity of the existing generation of hard drives ranges from about 8 GB to 300 GB (up from about 20 MB just a few years ago). Consequently, the probability that unrecoverable data errors (“hard errors”) can occur during hard drive read/write operations has increased significantly along with the substantial increase in storage capacity.
One hardware approach to solving the problem of increased hard errors in hard drives is Redundant Arrays of Independent Disks (RAID). The RAID approach connects a plurality of hard drives together and treats them as a single, logical unit. Consequently, a computer sees the plurality of drives as one, large hard drive that can be formatted and partitioned similar to that of a smaller, individual drive. The redundancy thus provided by the multiple hard drives of the RAID approach enhances the recovery of lost data due to hard errors, and also increases the performance of the computer system involved. As such, the multiple hard drive RAID approach provides an acceptable solution for large, desk-side computers and server applications. However, the use of multiple hard drives for redundancy is unsuitable for those relatively small computer systems or products where the primary design considerations are to minimize space, weight and cost.
Therefore, it would be advantageous to have an improved method and system for recovering lost data with redundancy in an individual hard drive.